Tension Link for Drill Floor Substructure Assembly

ABSTRACT

The present invention relates to a tension link drill floor level connection system for use on a drilling rig, as may be used in subterranean exploration. The present invention provides a tension link assembly for resisting separating forces incurred between sections of the substructure. In particular, the tension link assembly may be located at the drill floor level for resisting the separating forces imparted by “splayed” or wide leg mast structures that tend to separate substructure side boxes from the substructure center section. The present invention may be comprised of a first link element and a second link element with a tension link being connectable over the first and second link elements to resist separation between sections of the substructure. A latch mechanism may be utilized to prevent upward movement of the tension side boxes or center section relative to the drill floor or to one another.

TECHNICAL FIELD OF INVENTION

The present invention relates to a new tension link drill floor levelconnection system for use on a drilling rig, as may be used insubterranean exploration. The present invention provides a tension linkfor resisting separating forces incurred between sections of thesubstructure. In particular, the invention provides a mechanism at thedrill floor level that resists the separating forces imparted by“splayed” or wide leg mast structures that tend to separate substructureside boxes from the substructure center section. In an alternativeembodiment of the invention, a latch mechanism is also provided toprevent vertical movement of sections of the substructure.

BACKGROUND OF THE INVENTION

In the exploration of oil, gas and geothermal energy, drillingoperations are used to create boreholes, or wells, in the earth.Drilling rigs used in subterranean exploration must be transported tothe locations where drilling activity is to be commenced. Theselocations are often remotely located. The transportation of such rigs onstate highways requires compliance with highway safety laws andclearance underneath bridges or inside tunnels. This requirement resultsin extensive disassembly of full-size drilling rigs to maintain amaximum transportable width and transportable height with furtherrestrictions on maximum weight, number and spacing of axles, and overallload length and turning radius. These transportation constraints varyfrom state to state, as well as with terrain limitations. Theseconstraints can limit the size and capacity of rigs that can betransported and used, conflicting with the subterranean requirements todrill deeper, or longer, and reach horizontal wells more quickly,requiring larger rigs.

Larger, higher capacity drilling rigs are needed for deeper (orhorizontally longer) drilling operations, since the hook load for deeperoperations is very high, requiring rigs to have a capacity of 500,000lbs. and higher. Constructing longer, deeper wells requires increasedtorque, mud pump capacity and the use of larger diameter tubulars inlonger strings. Larger equipment is required to handle these largertubulars and longer strings. All of these considerations drive thedemand for larger rigs.

Modern high capacity drilling rigs are transported in sections andreassembled at the desired location. Typical assemblies include a pairof top and bottom side boxes on either side of a center section to formthe complete substructure. The mast is typically transported in threesections; the lower mast section, the center mast section, and the uppersection. The top of the substructure forms the drill floor. The mast isassembled and raised above the drill floor. Then the substructure israised, lifting the raised mast. The top sections of the substructureare connected to the center section at a location beneath the drillfloor.

Larger rigs require a wider base structure for strength and windstability, and this requirement conflicts with the transportabilityconstraint and the time and cost of moving them. The wide leg base andlarge loads of the higher capacity drilling rigs impart higher outwardforces at the drilling floor level where they are connected. Theconnection of the legs to the substructure is made at the top sideboxes. The outward forces urge the side boxes away from the centersection connected between them, pivoting at the connections beneath thedrill floor level.

It remains desirable to prevent the separation that occurs between thetop side boxes and the center sections on high capacity drilling rigs.It is desirable to accomplish this task affordably. It is also desirableto accomplish this task without significant modification to existing,conventional designs for drilling rigs. It is also desirable toaccomplish this task without adding significant time to the rig-up andrig-down procedures. It is also desirable to accomplish this taskwithout adding machine or crane work to the solution. It is alsodesirable to accomplish this task without having to engage manpowerbeneath the substructure.

In summary, the preferred embodiments of the present invention provideunique solutions to many of the problems arising from a series ofoverlapping design constraints, including design limitations, rig-up andrig-down, and cost constraints.

SUMMARY OF THE INVENTION

The present invention relates to a new tension link drill floorconnection system for use on a drilling rig, as may be used insubterranean exploration. The present invention provides a tension linkassembly for resisting separating forces incurred between sections ofthe substructure. In particular, the invention provides a mechanism atthe drill floor level that resists the separating forces imparted by“splayed” or wide leg mast structures that tend to separate substructureside boxes from the substructure center section.

In one embodiment, a drilling rig is provided, comprising a collapsiblesubstructure including a side top box and a center section connectableto the side top box. A drill floor is formed on the top side of the sidetop box and the top side of the center section. A first link element isformed on the side top box, near to the drill floor. A second linkelement is formed on the center section adjacent to the first linkelement. A tension link is connectable to the first and second linkelements, such that forces urging separation of the first and secondlink elements are resisted by the tension link.

In another embodiment, the tension link is connectable to the first linkelement and second link element from the drill floor. In anotherembodiment, the first link element, second link element, and tensionlink are located substantially at the drill floor level of the drillingrig.

In another embodiment, the first link element is a lug connected to theside top box. The second link element is a lug connected to the centersection. The tension link is connectable over the first and second linkelements, such that forces urging separation of the first and secondlink elements are resisted by the tension link.

In another embodiment, the first link element is a relief in the sidetop box, and the second link element is a relief in the center section.The tension link is insertable into the first and second link elements,such that forces urging separation of the first and second link elementsare resisted by the tension link.

In another embodiment, a latch mechanism is provided for preventingupward movement of the side top box and center section in relation toeach other as well as the drill floor.

In another embodiment, a method of preventing separation of the drillfloor of a drilling rig is provided. In this embodiment, the stepsinclude providing a first link element on the side top box, providing asecond link element on a center section at a location that issubstantially adjacent to the first link element, and providing atension link connectable to the first and second link elements toprevent separation of the first and second link elements. In thismethod, a latch mechanism may be provided adjacent the tension link forpreventing upward movement of the side top box and the center section inrelation to the drill floor as well as to one another.

As will be understood by one of ordinary skill in the art, the sequenceof the steps disclosed may be modified and the same advantageous resultobtained.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects and features of the invention will become more readilyunderstood from the following detailed description and appended claimswhen read in conjunction with the accompanying drawings in which likenumerals represent like elements.

The drawings constitute a part of this specification and includeexemplary embodiments to the invention, which may be embodied in variousforms. It is to be understood that in some instances various aspects ofthe invention may be shown exaggerated or enlarged to facilitate anunderstanding of the invention.

FIG. 1 is an isometric view of a drill floor level locking system havingcertain features in accordance with the present invention;

FIG. 2 is an isometric view of the drill floor level locking system withthe tension link removed to further illustrate certain features of thepresent invention;

FIG. 3 is an isometric view of the drill floor level locking systemhaving certain features in accordance with the present invention,including a latch mechanism for preventing upward movement of the sidebox and center section in relation to one another and the drill floor;and

FIG. 4 is an isometric view of the drill floor system shown in FIG. 3with the center section removed for clarity.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description is presented to enable any person skilled inthe art to make and use the invention, and is provided in the context ofa particular application and its requirements. Various modifications tothe disclosed embodiments will be readily apparent to those skilled inthe art, and the general principles defined herein may be applied toother embodiments and applications without departing from the spirit andscope of the present invention. Thus, the present invention is notintended to be limited to the embodiments shown, but is to be accordedthe widest scope consistent with the principles and features disclosedherein.

FIG. 1 is an isometric view of a drill floor level locking system havingcertain features in accordance with the present invention.

In this embodiment, a drilling rig 10 is provided (not shown),comprising a collapsible substructure 12 including a side top box 20,and a center section 40 connectable to side top box 20. A drill floor 30(not shown) is formed on the top side of side top box 20 and the topside of center section 40. Tension link assembly 100 is shown connectingside top box 20 and center section 40.

A first link element 102 is formed on side top box 20, near to drillfloor 30 (not shown). A second link element 104 is formed on centersection 40 adjacent to first link element 102. A tension link 106 isconnectable to first link element 102 and second link element 104, suchthat forces urging separation of first link element 102 and second linkelement 104 are resisted by tension link 106. In the embodiment shown,tension link 106 is generally ellipsoidal or elliptical in shape and hasa central recess for connection of first link element 102 and secondlink element 104. First link element 102, second link element 104, andtension link 106 may be formed of a suitably rigid material, such as ahard metal. In particular, tension link 106 may be formed to besufficiently strong to resist forces imparted on first link element 102and second link element 104 by separation of side top box 20 and centersection 40.

In another embodiment illustrated by FIG. 1, tension link 106 isconnectable to first link element 102 and second link element 104 fromdrill floor 30, preventing the necessity of sending a worker beneathdrill floor 30 to install tension link 106.

In another embodiment illustrated in FIG. 1, first link element 102,second link element 104, and tension link 106 are located substantiallyat the level of drill floor 30 of drilling rig 10.

In another embodiment illustrated in FIG. 1, first link element 102 is alug formed on side top box 20. Second link element 104 is a lug formedon center section 40. Tension link 106 is connectable over first linkelement 102 and second link element 104, such that forces urgingseparation of first link element 102 and second link element 104 areresisted by tension link 106. In another embodiment, a method ofpreventing separation of drill floor 30 of drilling rig 10 is provided.In this embodiment, the steps include providing a first link element onthe side top box, providing a second link element on a center section ata location that is substantially adjacent to the first link element, andproviding a tension link connectable to the first and second linkelements to prevent separation of the first and second link elements.

FIG. 2 illustrates tension link assembly 100 from FIG. 1 with tensionlink 106 removed for a better view of first link element 102 and secondlink element 104. More specifically, in the embodiment of tension linkassembly 100 shown in the present figure, a first link element relief103 and a second link element relief 105 are illustrated. First linkelement relief 103 is a relief in side top box 20. The relief may be,for example, semi-circular or triangular in shape. Second link elementrelief 105 is also a complementary relief in center section 40, and maygenerally have the same shape as first link element relief 103. Tensionlink 106 is insertable into first link element relief 103 and secondlink element relief 105, such that forces urging separation of firstlink element 102 and second link element 104 are resisted by tensionlink 106. By way of example, and not limitation, tension link 106 may be“bone shaped” so as to fit in opposing triangular shaped reliefs offirst link element relief 103 and second link element relief 105 of thisalternate embodiment.

FIGS. 3 and 4 are isometric views of an alternative embodiment oftension link assembly 100 having certain features in accordance with thepresent invention, including a latch mechanism 110 for preventing upwardmovement and disengagement of side top box 20 and center section 40 inrelation to one another as well as drill floor 30.

In FIG. 3, in the embodiment illustrated, latch mechanism 110 isprovided for preventing upward or vertically separating movement of sidetop box 20 and center section 40 in relation to each other. This in turnhelps to maintain the position of tension link 106 in relation to sidetop box 20 and center section 40 as well as drill floor 30. In apreferred embodiment shown, latch mechanism 110 is operable from abovedrill floor 30 so as not to necessitate sending a worker beneath drillfloor 30 to secure tension link 106 in place.

As illustrated, and also referring to FIG. 4, latch mechanism 110 mayhave a handle 112 and a latch 114 (FIG. 4) connected by a connector 118.Twisting handle 112 causes connector 118 and attached latch 114 torotate, thereby engaging a latch relief 116 (FIG. 4) to secure side topbox 20 and center section 40 in vertical alignment with one another andto resist disengagement of tension link 106 from first and second linkelements 102 and 104.

A handle relief 111 may be provided on both first link element 102 andsecond link element 104 within which handle 112 resides. A handlelimiter 113 may extend from link element 102 or 104 to limit the amountof rotation by handle 112. Handle limiter 113 may simply be a portion onfirst link element 102 and/or second link element 104 which has beenshaped to provide a stop to handle 112. Alternatively, handle limiter113 may extend from tension link 106.

FIG. 4 illustrates the alternative embodiment of tension link assembly100 with center section 40 removed for additional clarity. In thisfigure, latch 114, latch relief 116, and connector 118 may be morereadily seen located below handle 112. Additionally, it can be seen thathandle 112 is oriented to be substantially parallel with latch 114. Thatis, handle 112 and latch 114 may share the same vertical plane such thata well operator turning handle 112 may be certain through visualinspection that latch 114, hidden by first link element 102 and secondlink element 104, is properly oriented in either a locked or unlockedposition. Turning handle 112 rotates connector 118 and latch 114 tofacilitate the desired locking or unlocking operation.

In another embodiment of the invention, rather than having a handlelimiter 113 to limit rotation of handle 112, latch relief 116 mayinstead be converted to limit the rotation of latch 114, and handlelimiter 113 removed for free rotation of handle 112.

As will be understood by one of ordinary skill in the art, the sequenceof the steps disclosed may be modified and the same advantageous resultobtained. For example, the exact shape of first and second link elements102 and 104 and engaging tension link 106 can vary significantly andstill obtain the result of resisting separation.

Having thus described the present invention by reference to certain ofits preferred embodiments, it is noted that the embodiments disclosedare illustrative rather than limiting in nature and that a wide range ofvariations, modifications, changes, and substitutions are contemplatedin the foregoing disclosure and, in some instances, some features of thepresent invention may be employed without a corresponding use of theother features. Many such variations and modifications may be considereddesirable by those skilled in the art based upon a review of theforegoing description of preferred embodiments. Accordingly, it isappropriate that the appended claims be construed broadly and in amanner consistent with the scope of the invention.

1. A drilling rig, comprising: a collapsible substructure including: aside top box; a center section connectable to the side top box; and, adrill floor formed on a top side of the side top box and a top side ofthe center section; a first link element formed on the side top box,near to the drill floor; a second link element formed on the centersection; the first link and second link elements being located inadjacent alignment when side top box and center section are positionedfor connection to each other; and, an annular tension link connectableto the first and second link elements; wherein forces urging separationof the first and second link elements are resisted by the tension link.2. The drilling rig according to claim 1, further comprising: thetension link being connectable to the first link element and second linkelement from the drill floor.
 3. The drilling rig according to claim 1,further comprising: the first link element, second link element, andtension link being located substantially at the drill floor level of thedrilling rig.
 4. The drilling rig according to claim 1, furthercomprising: the first link element being a lug formed on the side topbox; the second link element being a lug formed on the center section;and, the tension link being connectable over the first and second linkelements.
 5. The drilling rig according to claim 1, further comprising:the first link element having a relief in the side top box; the secondlink element having a relief in the center section; and, the tensionlink being insertable into the first and second link elements.
 6. Thedrilling rig according to claim 1, further comprising: a latch mechanismfor preventing upward movement of the tension link assembly in relationto the drill floor.